Vibrational structure and partial rates of resonant Auger decay of the N 1s -> 2pi core excitations in nitric oxide

High-resolution resonant Auger electron spectra of NO measured in the vicinity of the N $1s \rightarrow 2\pi$ core excitations are presented. The open shell electronic configuration of the molecule results in four excited electronic states, three of which are populated in the photoabsorption spectrum, $^2\Delta$, $^2\Sigma^-$ and $^2\Sigma^+$. Electron emission spectra obtained at different vibrational levels of the three N~;$1s$ core-excited states of NO are reported. Recently reported ab initio calculations [J. Chem. Phys. 106, 4038 (1997)] are used to generate theoretical spectra for comparison with the experimental results taking lifetime vibration interference and Auger resonant Raman effects into account. Very good agreement is found for the lowest energy $X~;^1\Sigma^+$ final ionic state. Spectra of the higher energy final ionic states are decomposed into contributions from the different $5\sigma^-12\pi^1$ and $1\pi^-12\pi^1$ configurations for comparison of the calculated and experimental partial Auger decay rates. A revised value for the adiabatic ionization energy of the $^1\Delta$ ionic state results from the deconvolution